The properties of relaxor ceramics in the compositional series (1−x)K0.5Bi0.5TiO3–xBa(Ti0.8Zr0.2)O3 have been investigated. Values of Tm, the temperature of maximum relative permittivity, decreased from 380°C at x = 0.0 to below room temperature for x > 0.7. Compositions x = 0.1 and 0.2 were piezoelectric and ferroelectric. The maximum value of d33 piezoelectric charge coefficient, 130 pC/N, and strain, 0.14%, occurred at x = 0.1. Piezoelectric properties of x = 0.1 were retained after thermal cycling from room temperature to 220°C, consistent with results from high-temperature X-ray diffraction indicating a transition to single-phase cubic at ~300°C.